Patent GB-1505717-A (GB)
Title: Mounting assembly for retaining printed circuit boards
IPC: H05K7/14
Filed: 1975-03-27
Abstract: 1505717 Printed circuit board assemblies LICENTIA PATENT VERWALTUNGS GmbH 27 March 1975 [28 March 1974(2)] 12998/75 Heading H1R A mounting assembly 1 (Figs. 1, 2, and 3) retaining printed circuit boards 2 comprises similar side walls 3 securing upper and lower plastic members 4, 5 comprising longitudinal strips 6 parallel to the side walls and transverse strips 7, 13 at right angles thereto; the broad faces of the strips being vertical, thus the strips 6, 17, 18 form a grid. Right angled ends 8 of the side walls are notched for securing screws. Strips 6 project further into the assembly than do strips 7, and their projections 10 form with the ends 11 of strips 7 guide apertures 12 of standard spacing receiving circuit boards 2; the members 4, 5 being secured to the upper and lower ends of side walls 3. Transverse strips 13 forked into sections 14, 15 are provided at the front and rear ends of strips 6 and section 14 has an inward projection 16, while section 14 has an inwardly projecting edge 17 to cooperate in clamping strips 18 having threaded bores accessible through bores 19 of section 14. A front plate 20 at right angles to the plane of circuit boards 2 contains a grip member 2 and is secured to strip 18 by screws 22 engaging the threaded bores to retain the circuit boards 2. Each circuit board carries at its rear end a male multipoint plug connector 24 engaging on insertion a female multipoint connector 25 with connection terminal posts 26, parallel to which run bores at the upper and lower ends adjoining bores in retaining boards 27; projections 28 of clips 29 being inserted in the bores to fix the connectors 25 in position by resilient arms 30 engaging link members 32 of boards 27 which are screwed to sections 14 of strips 13. The spacing available for a circuit board is double the spacing of adjacent guides and air can flow through the interstices of adjacent circuit boards to cool the electrical components mounted thereon. In a modified assembly 1 (Fig. 4) four plastic members 34 to 37 are placed at the respective corners of the side walls 3 and each comprise two transverse strips 38, 39 spaced by longitudinal strips 40; strips 39 defining the forked sections 14, 15, projections 16, 17 and bores 19 with strips 40 parallel to strips 38, 39 at right angles to side walls 3. A free space extends between facing strips 38, 39, and strips 40 contain projections 10 defining with ends 11 of strips 38, 39 the guides into which circuit boards 2 are insertable. Handles 21 are fitted to the fronts 20 of the circuit boards, while straps 40 are tapered at their ends and the mouths of the guides are widened to facilitate insertion. The plastic members may be injection moulded in a three-part separable tool, and members 4, 5, 34 to 37 may be electrolytically coated with metal to provide electromagnetic screening. A modified assembly (Figs. 5, 6 and 7, not shown) comprises similar side members retaining plastic profiled rails with equally spaced projections therealong separated by equal gaps admitting the insertion of circuit boards; the rails having L-shaped ends extending into grooved edge sections. U-shaped guide holders connected to transverse strips extend parallel to the side members and secured thereto, and are formed as a plastic unit. The U openings of the guide members are coplanar with the gaps for the circuit boards, which may carry facing boards with grip members and at the rear edge a male multipoint connector engaging a corresponding female connector with protruding connecting wires which are screwed to boards carried by the rear profile rails. The guide members are reinforced by a central strip and are separated by an opening for cooling air between adjacent circuit boards. The profile rails, guide holders and transverse strips may be electrolytically coated with metal for screening; earthed over metal side connections.